James
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| posted on 10/12/11 at 06:48 PM |
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BEC donor of the future?
BEC donor of the future?
I went to the NEC bike show a couple of weeks ago.
Spent some time looking at the BMWs and sitting on the 1000rr. In terms of a BEC: 200ish bhp out of 1lt is great... but not if it's only at
13000rpm or whatever!
What did stick in my mind for potential BEC donorage was the 1600gtl. It's a 1600, straight 6. It's 'only' 160bhp but it makes
it at 5000rpm (according to the blurb next to the bike) and more notably it's got 170Nm of torque. How does this compare with the Fireblades,
R1's etc. etc. that we use?
http://www.topspeed.com/motorcycles/motorcycle-reviews/bmw/2012-bmw-k-1600-gt-and-k-1600-gtl-ar97581.html
So looks like it's got a lot of advantages- ie. lightweight engine and box of a bike, but decent torque levels and will have a nice 6-pot
soundtrack. Guessing it's shaft drive too to presumably easy to connect to a diff.
Realise it'll not be the most common donor around and no wonder what sort of price they'll break at.
Thoughts?
Cheers,
James
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"The fight is won or lost far away from witnesses, behind the lines, in the gym and out there on the road, long before I dance under those lights."
- Muhammad Ali
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matt_gsxr
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| posted on 10/12/11 at 07:18 PM |
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From the marketing bumf.....
>Supreme in-line 6-cylinder engine with a high level of pulling power, especially in the lower and medium engine speed range.
>Engine output 118 kW (160 bhp) at 7 750 rpm and maximum torque 175 Nm at 5 250 rpm.
>Over 70 per cent of the maximum torque is already available from 1 500 rpm.
>The lightest and most compact 6-cylinder in-line engine in serial motorcycle production > 1000 cc weighing just 102.6 kg and measuring 555 mm
in width.
With a rev limit of 8k this is more comparable with a mr2 engine or k-series.
So, it sits in that compromise between all out lightweight bec and lightweight car engine.
Interesting
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clairetoo
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| posted on 10/12/11 at 07:31 PM |
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Not too sure how you would go about fitting this into a BEC ?
Its cuz I is blond , innit
Claire xx
Will weld for food......
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Dangle_kt
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| posted on 10/12/11 at 08:27 PM |
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I dont see the point, personally the high reving nature of becs is what makes them what they are.
More torque wouldn't be a bad thing - but a 8k rpm ceiling would mean I'd rather have a s2000 lump or something.
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adithorp
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| posted on 10/12/11 at 08:31 PM |
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quote:
Originally posted by James
200ish bhp out of 1lt is great... but not if it's only at 13000rpm or whatever!
James
Why?
The problem I've been told would be getting around all the traction control, security, etc in the bike loom. I talked to someone earlier this
year who'd been to spain for a bike track day and him and his mates couldn't get anywhere near to 2 1000rr that were there on thier
ex-race bikes.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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matt_gsxr
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| posted on 10/12/11 at 10:30 PM |
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quote:
Originally posted by adithorp
The problem I've been told would be getting around all the traction control, security, etc in the bike loom.
You could just fit aftermarket ECU (megasquirt for example). Cost would is no greater than the cost of a power commander.
There do seem to be tools out there for hacking the BMW ecu's but they seem to be pretty expensive compared to the free knowledge on some of the
japanese kit.
I bet one of these engines would work nicely in a reverse trike
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blakep82
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| posted on 11/12/11 at 12:13 AM |
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quote:
Originally posted by clairetoo
Not too sure how you would go about fitting this into a BEC ?
mid engine perhaps?
bit like a car engine with a transaxle maybe?
yeah, just seems like a car engine in a bike though... quite like the idea of a 1.6 staight 6 though. sounds like fun
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scootz
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| posted on 11/12/11 at 11:49 AM |
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I'd still rather sacrifice 12 of those ft/lbs to have the 40 extra ponies of the ZZR1400!
It's Evolution Baby!
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scootz
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| posted on 11/12/11 at 11:50 AM |
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As for positioning... middy - hooked straight up to a reverse box which is hooked straight up to a diff!
It's Evolution Baby!
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ffrgtm
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| posted on 14/12/11 at 06:26 AM |
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quote:
Originally posted by scootz
I'd still rather sacrifice 12 of those ft/lbs to have the 40 extra ponies of the ZZR1400!
HP is just a calculation derived from torque and speed.... it basically doesn't exist. Power = work (which is torque) * time (rpm... or
radians/sec in metric). If you geared the bmw engine to "see" the same wheel speed that the saki' saw then you'd have more
power with the bmw.
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phelpsa
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| posted on 14/12/11 at 07:59 AM |
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quote:
Originally posted by ffrgtm
quote:
Originally posted by scootz
I'd still rather sacrifice 12 of those ft/lbs to have the 40 extra ponies of the ZZR1400!
HP is just a calculation derived from torque and speed.... it basically doesn't exist. Power = work (which is torque) * time (rpm... or
radians/sec in metric). If you geared the bmw engine to "see" the same wheel speed that the saki' saw then you'd have more
power with the bmw.
Power is power. It doesn't change with gearing. If the BMW produces less power than the zzr then it can't suddenly make more at the
wheels!
Torque is the mystical figure that means nothing until it reaches the road. Power is the useful one.
[Edited on 14-12-11 by phelpsa]
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ffrgtm
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| posted on 14/12/11 at 11:25 AM |
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HP = [ 2*PI*n(rpm)*T(ft-lbs) ] / 33,000 which is roughly = [ n * T / 5250 ]
Ever notice how on every dyno plot the torque crosses hp at exactly 5250? It's not magic... it's a byproduct of the completely calculated
figure of HP.
You can see by this equation that if an engine has more torque at a lower rpm you can simply keep cranking up rpm to get more power... this torque
that's actually going into accelerating the vehicle runs through gear ratios which are a very simple ratio.
I can agree that I was more than fuzzy with the whole "sees" thing, but I will say that the relationship between inertia is more complex
when you try to translate it through gear ratios.... Inertia or Impedance = (dest/source)^2
So while I'm claiming you can just trade torque for more HP by changing gearing... it doesn't always work out that way in real life.
I still disagree with the sentiment that torque is the made up figure though.... the rate at which the engine is producing the torque can always be
changed... but the actual mechanical advantage the pistons have on the crank shaft isn't going change.
More than likely I have something backwards in my understanding though 
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bobinspain
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| posted on 14/12/11 at 01:49 PM |
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quote:
Originally posted by ffrgtm
HP = [ 2*PI*n(rpm)*T(ft-lbs) ] / 33,000 which is roughly = [ n * T / 5250 ]
Ever notice how on every dyno plot the torque crosses hp at exactly 5250? It's not magic... it's a byproduct of the completely calculated
figure of HP.
You can see by this equation that if an engine has more torque at a lower rpm you can simply keep cranking up rpm to get more power... this torque
that's actually going into accelerating the vehicle runs through gear ratios which are a very simple ratio.
I can agree that I was more than fuzzy with the whole "sees" thing, but I will say that the relationship between inertia is more complex
when you try to translate it through gear ratios.... Inertia or Impedance = (dest/source)^2
So while I'm claiming you can just trade torque for more HP by changing gearing... it doesn't always work out that way in real life.
I still disagree with the sentiment that torque is the made up figure though.... the rate at which the engine is producing the torque can always be
changed... but the actual mechanical advantage the pistons have on the crank shaft isn't going change.
More than likely I have something backwards in my understanding though
The 5250 number prompted me to look at "How Stuff Works" online.
It's pretty interesting (but heavy) stuff.
Turns out 33,000ft.lbs of work/min = 1 HP.
33,000/2Pi = 5252.
HP=Torque x RPM divided by 5252.
So to generate more horse power for a given torque, increase the RPM. (shorter stroke, smaller bore etc).
I didn't venture into the inertia stuff. (After all, as Clint Eastwood's creation Harry Callahan would say, "A man's gotta
know his limitations."
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phelpsa
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| posted on 14/12/11 at 07:00 PM |
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quote:
Originally posted by ffrgtm
HP = [ 2*PI*n(rpm)*T(ft-lbs) ] / 33,000 which is roughly = [ n * T / 5250 ]
Ever notice how on every dyno plot the torque crosses hp at exactly 5250? It's not magic... it's a byproduct of the completely calculated
figure of HP.
You can see by this equation that if an engine has more torque at a lower rpm you can simply keep cranking up rpm to get more power... this torque
that's actually going into accelerating the vehicle runs through gear ratios which are a very simple ratio.
I can agree that I was more than fuzzy with the whole "sees" thing, but I will say that the relationship between inertia is more complex
when you try to translate it through gear ratios.... Inertia or Impedance = (dest/source)^2
So while I'm claiming you can just trade torque for more HP by changing gearing... it doesn't always work out that way in real life.
I still disagree with the sentiment that torque is the made up figure though.... the rate at which the engine is producing the torque can always be
changed... but the actual mechanical advantage the pistons have on the crank shaft isn't going change.
More than likely I have something backwards in my understanding though
Take it back to very basics, ie what energy goes in must come out. Assuming time is constant (dangerous these days!) what power goes in must come out.
You can't create energy.
Torque curves etc are just a method of measuring how well an ICE is able to convert the energy stored in the fuel into useful mechanical energy at a
given engine speed. As you have worked out, it is just a power curve (what the dyno measures, useful power) with the power divided by the RPM/5250 (if
its bhp and lb/ft).
Torque, inertia etc etc are just methods of transferring energy, it can't create it.
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